Method of regulating shunt commutator motors



Dec. 6, 1949 v. KLl'MA 2,490,274 I METHOD OF REGULATING SHUNT COMMUTATOR MOTORS I Fil ed Feb. 14, 1948 Fi .4 Fi 2 Uill'zm XML-ma.

zgsoau;

METHDDiQE (RE GIJL'ATING SHUNT- COMMUTATORZMDTORS vil m Kliina, rague, Cz cho lovakia,.assi p n of one-halt to. Moravian Electrical Engineering- Works,- National corporation Olomo'um Czechoslovakia Section}; Public 122M630, August 8, 1946 Patent expires Decembepfit lBGB' 7 Claims, (01. 318-244) 2'2." This inventionrelatesto regulatin'g transform Fig. ,2r;isaag,-vec.tor diagram of, 'voltagerelations. ersior. po s/phase shunt ommutatorAt tmotors. iDYOIYBd-inathB control. and more particularly to the control; oi, such- Reicnring ;to;Fig. 1,= a:.shunt commutator polye.

transformers arrangedsfonuse wit such: motors Dh1aSB. Ai Q..mOtOI-, is-illustratedas having a three-.v in which both thee-stator. andgroto vare.supplied 5 phaseistator winding; 1,. connected. to; a three- WithtCilIfI'El'l-ti. phasezAi. C. supp1y;.lin,e,- and 3.1.1017012, having The;kn.0Wn methodsof-regulating:thespcedxoitwo setsiofgthree commutatorbrushes, 9, ID. A; shunt commutator polyphase A:,C;. motors inregulating transformer-isiillustrated ashaving elude-applying; to the. rotor a. varyin voltage primarywindings 3;, connected tothe supplyline; derivedfrom, a;single or. double. induction regui 1i]; and secondary windings 4i lator; changingtapsgon the stator windin s; org In accordance with the invention, windings 4 utilizing a,regulating-1.transformer-having taps; have bare or uninsulated portionsfor current connected :to a, control panel. having a. commu, conducting vengagementby. movable or adjustable tator- ;type control, arrangement. contacts 5;.and.v 6,. which arepreferably rolling.

In manyrespects, these;known speedgregulaf 16;.- conta-cts. Contacts. 5,- fit-move.simultaheouslyin ing arrangements arerunsatisfactory.andunduly. relatively.opposeddirections.overthe bare'dporexpensive; If the speed regulation is stepless, tionsmiawindinga l; sothat the.;voltage derived. it is expensive and has a large reactance imfrom these windings varies from a minimum to; pairing the efficiencyoithe motor. A step by a maximum. step control is less expensive, but the substantial 2a Contactsttapply; this .derivedvoltage to the potential between successive contacts results in commutator--brushes. 9,. whereaseach brush 5;.is; burning and pitting of the contacts. connected ;to.a. winding]. Thelatterhave the.-

For sub-synchronous and: super-synchronous samephase relation-as windingsd; Each winding. speed regulation, the regulating voltage should, I. is :co ected.-in.series circuitrelation. with an be ,variable not only in value butalso inphaJsQ. -e nd;of a.winding.8,z which-.windingsare arranged; Consequently,- it has been the practice to employ in a phase..relationidiffering.fromthatof wind:-.

several sets of windings in thefregulatinggtra ns ings' 4-iand'1; Theother.ends-of. windings dare, former, fil ng one set. for.the-.S11b-SY; Ghr0 connected-to:.commutator.:brushes 10.; nous speed range and. another set. for the supere The. primarynwindingsfi.areidi-vided. into windsynchronous speed range. {it} ings 3atand.3b; arrangedon different cores. Each;

To obviate the foregoing difiiculties, the preswinding 3b is in series circuit relation with a ent invention includes a winding or windings winding 3a, and windings 31) may be regulated having bare or uninsulated portions so that a or adjusted as schematically illustrated. Windpair of brushes may be moved in opposing direcings 31) have a value for super-synchronous speed tions along the bared portions of the windings. 35 which is opposite to that for sub-synchronous A continuous stepless speed control is provided speeds, and are conveniently regulated in accordby means of which the speed may be varied from ance with the speed difference in either direction a negative maximum to a positive maximum. from synchronous speed. Phase shifting windings are in circuit connec- Referring to Fig. 2, the secondary voltage is the tion with the regulated windings to introduce a 4g vector sum of the voltages in windings 4, l and desired relative phase variation. 8, so that it varies from a vector value 0A to It is an object of the present invention to proa vector value OB. With such variation, the vide a novel regulating transformer for speed voltage of windings 4 varies from the vector value control of a shunt commutator polyphase A. C. CA to the vector value CB. By moving contacts control. 45 5, 6 in opposite directions over the bare portions Another object is to provide suchatransformer of windings 4, the vector value of the voltage including phase shifting means. of windings 4 is varied to vary the phase of the These and other objects, advantages, and novel total secondary voltage. The transformer secfeatures of the invention will be apparent from ondary voltage is out of phase with the motor the following description and the accompanying 50 secondary voltage when the stationary voltage drawing. U2o=OD. The transformer secondary voltage In the drawing: Ureg, varying from CA to CB has such a value Figs. 1 and 3 are schematic wiring diagrams of and phase relative to the motor secondary voltcontrol arrangements incorporating the invenage that the latter is correctly compensated at tion. 56 all speeds.

For small motors, only three commutator brushes are needed, so that brushes 9 can be omitted and contacts 6 be shunted or short cir-' cuited. Within a certain speed range either side of synchronous speed, windings 8 may be omitted. These windings provide for phase variation of the compensating component, so as to provide proper compensation for speeds both above and below synchronous. Under no-load conditions, increased compensation with decreased speed can be effected by simultaneous adjustment of windings 8 and 312. If the load is constant, adjustment of Winding 8 is not necessary. With axial supplying of rotor 2, the regulating transformer can be delta-connected, reducing the load on contacts 5, 6 by one-half.

For higher motor outputs, the arrangement of Fig. 3 is useful. In this arrangement, an intermediated transformer, comprising windings H, l2, I3 is interposed between the rotor 2 and the regulating transformer. At such outputs, the motor requires heavy currents at low voltages, and it is more advantageous for the regulating transformer to work with higher voltages and lower currents. The arrangement of windings 4 as in Fig. 1 may be used instead of the connection of windings 3b and 8 as shown in Fig. 3.

The intermediate transformer can be used to increase the number of phases, such as changing three-phase to twelve-phase. Thus in Fig. 3, l2,

l3 are two secondaries on one core, the other two cores being omitted for simplicity.

While specific embodiments of the invention have been shown and described in detail to illustrate the principles of the application thereto,

it should be understood that the invention may be otherwise embodied without departing from such principles.

Iclaim:

1. In a speed regulating arrangement for shunt commutator polyphase A. 'C. motors having a commutator with two sets of brushes, a regulating transformer for applying compensating potentials to the commutator comprising, in com- 'bination, secondary windings having uninsulated portions arranged for current conducting engagement by movable contacts; two sets of adjustable contacts movable simultaneously in opposed directions along such uninsulated winding portions to vary the potential derived from the windings; and circuit means connecting each set of brushes to a different set of adjustable contacts.

2. A transformer as claimed in claim 1 including additional windings on the same cores as said secondary windings and connected in series between one set of contacts and one set of brushes.

3. A transformer as claimed in claim 1 inveluding additional windings on the same core as said secondary windings, in series with the windings being adjustable as to ampere turns.

5. A transformer as claimed in claim 1 in which the transformer primary windings are arranged in two sections on cores having different phase relations.

6. A transformer as claimed in claim 1 including an intermediate transformer between said secondary windings and the commutator to reduce the commutator voltage and increase the commutator current.

7. A transformer as claimed in claim 1 including an intermediate transformer between said secondary windings and the commutator to reduce the commutator voltage and increase the commutator current, the secondary windings of said intermediate transformer having a greater number of phases than the secondary windings of said regulating transformer. VILEM KLIMA.

REFERENCES CITED ,The following references are of record in th file of this patent:

UNITED STATES PATENTS Number Name Date 1,438,854 Piper Dec. 12, 1922 2,137,877 Kramer Nov. 22, 1938 2,192,050 Norcross Feb. 27, 1940 2,233,842 Leischner Mar. 4, 1941 2,325,470 Bonanno et a1 July 27, 1943 

